The Flowserve Valtek Mark Six is a globe-style, single-seat, top-entry automatic control valve with a fabricated extension for cold box cryogenic applications to -425°F/‑218°C. Mark Six bodies are constructed of bronze or austenitic stainless steel for high impact strength at low temperature and minimum heat transfer. Mark Six is designed for high flow capacity with a minimum of mass to reduce boil-off on valve cool-down.